ConfigurationBuilder Classe

Definizione

public ref class ConfigurationBuilder abstract : System::Configuration::Provider::ProviderBase

public abstract class ConfigurationBuilder : System.Configuration.Provider.ProviderBase

type ConfigurationBuilder = class
    inherit ProviderBase

Public MustInherit Class ConfigurationBuilder
Inherits ProviderBase

Ereditarietà

Object

ProviderBase

ConfigurationBuilder

Esempio

L'esempio seguente illustra come implementare un semplice ConfigurationBuilder per leggere le variabili di ambiente:

using System;
using System.Configuration;
using System.Xml;

namespace Samples.AspNet.Config
{

   public class SampleConfigurationBuilder : ConfigurationBuilder
    {

        public override XmlNode ProcessRawXml(XmlNode rawXml) 
        {

            string rawXmlString = rawXml.OuterXml;

            if (String.IsNullOrEmpty(rawXmlString)) {
                return rawXml;
            }

            rawXmlString = Environment.ExpandEnvironmentVariables(rawXmlString);

            XmlDocument doc = new XmlDocument();
            doc.PreserveWhitespace = true;
            doc.LoadXml(rawXmlString);
            return doc.DocumentElement;
        }

        public override ConfigurationSection ProcessConfigurationSection(ConfigurationSection configSection) 
            => configSection;
    }
}

Imports System.Configuration
Imports System.Xml

Public Class SampleConfigurationBuilder : Inherits ConfigurationBuilder

    Public Overrides Function ProcessRawXml(rawXml As XmlNode)  As XmlNode

        Dim rawXmlString As String = rawXml.OuterXml

        If String.IsNullOrEmpty(rawXmlString) Then
            Return rawXml
        End If

        rawXmlString = Environment.ExpandEnvironmentVariables(rawXmlString)

        Dim doc As New XmlDocument()
        doc.PreserveWhitespace = True
        doc.LoadXml(rawXmlString)
        Return doc.DocumentElement
    End Function

    Public Overrides Function ProcessConfigurationSection(configSection As ConfigurationSection)  As ConfigurationSection
       Return configSection
    End Function

End Class

L'esempio seguente è un estratto del file di configurazione applicato all'esempio precedente. Ciò applica le variabili di ambiente alla configurazione di appSettings e rende tali valori disponibili in ConfigurationManager.AppSettings.

<!-- To declare and use Configuration Builders in your configuration chain, update your app.config or web.config file as follows:  -->

<configSections>
  <section name="configBuilders" type="System.Configuration.ConfigurationBuildersSection, System.Configuration, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" restartOnExternalChanges="false" requirePermission="false"/>
</configSections>

<configBuilders>
  <builders>
    <add name="SampleConfigurationBuilder" type="CustomConfigBuilders.MyConfigBuilder, CustomConfigBuilders" />
  </builders>
</configBuilders>

<!-- To apply Configuration Builders to a configuration section, use the 'configBuilders' tag as follows:  -->
<appSettings configBuilders="SampleConfigurationBuilder">
  <add key="COMPUTERNAME" value="Will Be Replaced by EnvironmentVariable" />
</appSettings>

Commenti

Derivare da questa classe per leggere la configurazione da un'origine esterna che si vuole usare nell'applicazione .NET Framework usando l'API standard ConfigurationManager .